What Cryptex says is true. I just wanted to add that there's another possibility. I don't know if I'm getting the details right, but apparently some botters know how to steal IP addresses as a method for covering their tracks, so when they bot they essentially "disguise" their IP address with an innocent user's IP address. I don't know how they do it or any other details, only that it happens and that I've come across a couple of users who were banned for botting and were given their accounts back after an investigation found that someone had used them in the method described above.
To contest the ban, fill out a
customer support ticket and respond to it regularly.